1. Field of the Invention
The present invention generally relates to fleet vehicle reliability and mission assurance and, more particularly, the present invention relates to improving overall platform reliability and logistic reliability for a fleet of vehicles or platforms, such as aircraft.
2. Background Description
Reliability of a large fleet of vehicles or platforms, such as a fleet of aircraft, is the cumulative reliability of all aircraft in the fleet. So, it may be critical to know the relative health of particular platform relative to the fleet as a whole. For example, it is important for mission success that aircraft selected for a vital mission do not suffer a component failure during the mission. A component failure that causes one or more aircraft to abort the mission may result in mission failure. If one knows individual aircraft reliability prior to selection, one can avoid selecting compromised aircraft or, at least perform preventative maintenance on those compromised aircraft prior to embarking on the mission.
So, improving fleet reliability requires improving the reliability of individual aircraft. Improving the reliability of each individual aircraft requires improving reliability of every component in each aircraft. Currently, fleet health is predicted manually using a broad-brush “best guess” approach. Maintenance personnel estimate the health of individual aircraft and overall fleet health based on intuition guided by top-level maintenance history records. Typically, no matter how experienced the maintenance personnel, personal experience of even several people cannot encompass all available data, i.e., no one knows everything. Consequently, these best guess predictions, based on maintenance personnel experience and intuition, are both imprecise and inaccurate.
One way to improve the reliability of such predictions is by pin pointing those aircraft that are the highest risk of some type of problem. Once problem aircraft are identified, those aircraft may be excluded from upcoming tours or repaired before deploying. However, addressing such problems, may require identifying aircraft components that are likely to fail. Once identified, those failing components may be replaced, providing spares are on hand for replacements. With the prior best guess approach, using available data and a number of gross assumptions to estimate the reliability, it was hit or miss, not only whether a potential problem might be anticipated, but even whether sufficient spares were available in inventory when a part failed.
Inventory stock may be ordered, for example, based on consumption history for the fleet. However, parts that were installed during that previous period are relatively new and each component that had been installed prior to the last quarter is one quarter older. In most cases, the newer parts are less likely to fail and older parts more. In another example, the available failure data for military applications is seldom based on similar (to current) operating conditions. Military aircraft may be deployed to a humid jungle one month and to a desert the next.
Consequently, gross assumptions based on history vary too widely to provide reasonably accurate or consistent estimates. As a result, various programs may suffer from wildly divergent product reliability estimates with subsequent cost and schedule estimating errors. Inventory may be oversupplied with a previously failing part and undersupplied for a part, e.g., a part that has a relatively large population approaching end of life. Failure to have sufficient quantities of the correct replacement parts on hand, at the very least, impairs fleet readiness and may cause the failure of an entire mission.
Accordingly, there is a need for accurate fleet wide aircraft failure prediction to identify aircraft that are unlikely to complete an assigned mission and, more particularly, for an accurate fleet wide aircraft component failure prediction for inventory control and optimization to improve the likelihood of identifying and repairing those fleet aircraft that are otherwise unlikely to complete an assigned mission.